Numerical Simulation of Turbulent Flow around an Airfoil with Blunt Trailing Edge

This paper is a computational study of the behaviour of aerodynamic characteristics of an airfoil with blunt trailing edge and investigates the effects caused by modifications made to the trailing edge, on aerodynamic performance. Blunt trailing edge airfoils are of interest in the engineering of large wind turbine blades because they allow for a strong structure with a high aerodynamic lift to structural weight ratio. Blunt trailing edge airfoils would not only provide a number of structural benefits, such as decreased structural volume and ease of fabrication and handling, but they have also been found to improve the lift characteristics of thick airfoils. The incorporation of blunt trailing edge airfoils would allow blade designers to more freely address the structural demands without having to sacrifice aerodynamic performance. These airfoils do have the disadvantage of generating high levels of drag as a result of the low-pressure steady or periodic flow in the near-wake of the blunt trailing edge. Also vortex shedding in these airfoils induces fluctuating loads and radiated noise. In the present investigation, we tested the effects of two cavities on the base drag and wake of an airfoil with blunt trailing edge. In two-dimensional subsonic flows, any method that increases the base pressure of the airfoil with blunt trailing edge consequently reduces the base drag. The base pressure increases subsequent to the introduction of the cavity to the trailing edge. Moreover the cavity causes the trapping and stabilizing of the vortex.